1. Technical Field of the Invention
The present invention relates to a contactless tag and also relates to an electronic circuit for the contactless tag used in a Radio Frequency IDentification (RFID) tag or a RFID card.
2. Description of the Related Art
An electronic circuit for a contactless tag includes an antenna that receives data for communication with a reader/writer. In a conventional electronic circuit, a signal received by an antenna is rectified, thereby forming a power supply.
For installation of a memory or a display unit, it is conceivable to use a secondary battery that can be charged within seconds. The charging time of the secondary battery has a high charging rate of 1:1. The current of the battery capacity is given by the following equation:Charging Time≅1 mA/h÷1 mA=1 hourwhere the secondary battery capacity=3 V, 1 mA/h, and the charging current=1 mA. A problem occurs in that it takes a long time to fully charge the battery.
The present invention has been made in view of this problem with conventional electronic circuit, and it is an advantage of the present invention to provide an electronic circuit for a contactless tag that can be fully charged in a short period of time, and to provide a contactless tag.